JPS6038630B2 - Method of manufacturing a heat insulating wall - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a heat insulating wall body comprising a frame filled with a heat insulating resin.

Conventionally, when manufacturing an insulating door for a refrigerator, for example, a stock solution of foamable urethane resin is injected into the box-shaped door frame, and the foaming of this stock solution causes the urethane foam as an insulating resin to form into the door frame. I allow myself to be filled with it.

However, since the urethane foam formed in this way tightly adheres to the door frame, for example, if a relatively large air pocket is created in the urethane foam during the foaming process, the urethane foam will locally contract during cooling, and this shrinkage will occur. As a result, the surface of the door frame becomes partially dented. This dent is very conspicuous due to the degree of light reflection, and there is a problem in that it significantly deteriorates the appearance of the product. The present invention has been made under the above circumstances, and its purpose is to easily separate the resin from the frame so that even if the resin inside the frame shrinks locally during cooling, etc., only the resin can be removed. To provide a method for manufacturing a heat insulating wall body which can prevent the shrinkage of the wall body and the formation of dents in the frame body.

An embodiment in which the present invention is applied to the manufacture of a heat insulating door for a refrigerator will be described below with reference to FIGS. 1 to 4.

First, Fig. 1 shows the finally obtained insulation door 1 of the refrigerator, and in this Fig. 1, 2 is the closing part 3 on the back
4 is a urethane foam as a heat insulating resin filled in the door frame 2 as will be described later. The boundary surface portion in contact with the front plate 2a is a relatively fragile brittle layer 5, unlike other portions. 6 is a template paper layered on the surface of the urethane foam 4, and 7 is a door frame 2.
A door inner plate 8 attached to close the closing portion 3 of the door is a door seal. Next, a method of manufacturing the above-mentioned heat insulating door 1 will be explained with reference to FIGS. 2 to 4.

9 is a lower part having a rectangular concave portion 9a, and 10 is a convex portion 10a.
This is a top tool that is placed over the bottom tool 9.

Reference numeral 11 denotes a cooling plate formed on the bottom surface of the recess ga of the lowering tool 9. Although not shown, this is formed by, for example, a cooling pipe buried in a meandering manner, and is cooled by flowing cold water through the cooling pipe.

First, the door frame 2 is stored in the recess 9a of the lowering tool 9 so that the doorway 3 thereof faces upward. In this state, door frame 2
The front plate 2a is in close contact with the cooling plate portion 11 of the lower jig 9. Then, a predetermined amount of a stock solution 13 of foamable urethane is injected into the door frame 2 from the injection machine 12 (see FIG. 2), and a Kamikoku odor 10 is applied through the template paper 6. Then, the stock solution 13 immediately foams, and the foamed urethane foam 4 moves violently while increasing the internal temperature due to the heat of reaction.
to fill up. Then, after a predetermined period of time has elapsed, the reaction gradually subsides, and the internal temperature reaches its maximum point (in this example, 8
After 0 to 120 seconds) Cool water is circulated through the cooling pipe to cool the cooling plate portion 11 of the lowering tool 9. As a result, the front plate 2a of the door frame 2 is rapidly cooled, so that only the boundary surface portion of the urethane foam 4 that is in contact with the front plate 2a is rapidly cooled, and as a result, the urethane foam 4 other than both boundary portions is rapidly cooled.
Although the growth of the urethane foam 4 proceeds normally even with residual heat, normal growth is inhibited only in the urethane foam 4 at the interface portion, and as a result, a brittle layer 5 with poor adhesion is formed only at the interface portion in contact with the front plate 2a. Ru. Next, the lifting tool 10 is removed, the door frame 2 filled with urethane foam 4 is taken out from the lower jig 9, the whole is slowly cooled, and the door inner plate 7 and door packing 8 are attached to complete the heat insulating door 1. . by the way,
For example, if a relatively large air pocket is generated inside the urethane foam 4 during the formation process, the urethane foam 4 will shrink particularly in this air pocket when the door frame 2 is taken out from the lowering tool 9 and slowly cooled. Sometimes I try. However, in this embodiment, a fragile layer 5 is provided in the portion of the urethane foam 4 that is in contact with the front plate 2a of the door frame 2.
is formed, so even if the above-mentioned partial shrinkage force acts on the urethane foam 4, the brittle layer 5 will partially break due to this shrinkage force, and the urethane foam 4 will peel off from the front plate 2a. In the end, only the urethane foam 4 contracts (see FIG. 4). This results in
Since the contraction force of the urethane foam 4 no longer reaches the front plate 2a, it is possible to prevent the front plate 2a from following the contraction of the urethane foam 4 and causing a dent. In this embodiment, the best time to rapidly cool the front panel 2a after injecting the stock solution 13 into the door frame 2 is after the internal temperature of the foamed urethane foam 4 has reached its maximum point as described above. preferable.

This is because if the urethane foam 4 is cooled while it still has fluidity, the brittle layer that has begun to form due to cooling may be immediately destroyed by the flow of the urethane foam. In order to make it easier to separate the urethane foam 4 and the front plate 2a, it is necessary to twist the front plate 2a after the fragile layer 5 is formed, for example, about 60 seconds after starting the rapid cooling of the front plate 2a. It is effective to apply force to make the fragile layer 5 of the urethane foam 4 fragile in advance. Further, the method for cooling the front plate 2a is not limited to the one shown in this embodiment. For example, as shown in FIG. The front plate 2a may be rapidly cooled by forming a passage 14 and supplying cold air to the cold air passage 14.

Furthermore, it goes without saying that the resin filled into the door frame 2 is not limited to urethane, and may be, for example, foamed urea resin. As described above, the present invention is characterized in that after injecting the stock solution of the heat insulating resin into the frame, the surface of the frame is rapidly cooled to form a brittle layer on the resin surface in contact with the frame. As a result, even if the resin filled in the frame shrinks unevenly, the fragile layer will break and the resin and frame will easily separate, so the shrinkage force of the resin will be applied to the frame and the frame surface will be damaged. It is possible to provide a method for manufacturing a heat insulating wall body that can prevent the occurrence of dents in the wall body.

[Brief explanation of drawings]

Figures 1 to 4 show an embodiment of the present invention, with Figure 1 being a sectional view of a heat insulating door, Figures 2 and 3 being sectional views showing different situations during the manufacture of the door, and Figure 4 5 is an enlarged sectional view of the external portion, and FIG. 5 is a view corresponding to FIG. 3 showing another embodiment of the present invention. In the figure, 1 is a heat insulating door, 2 is a door frame (frame body), 4 is a urethane foam (resin), 5 is a fragile layer, 11 is a cooling plate part, 13 is a stock solution, and 14 is a cold air passage. Figure 2 Figure 3 Figure 1 Figure 4 Figure 5

Claims (1)

[Claims] 1. In a device that manufactures a heat insulating wall by filling a frame with a heat insulating resin, after injecting the resin stock solution into the frame, the surface of the frame is rapidly cooled to cool the resin surface in contact with the frame. A method for producing a heat insulating wall, characterized in that a brittle layer is formed in the wall.